<template>
  <div class="drag" ref="dragDiv">
    <div class="drag_bg"></div>
    <div class="drag_text">{{ confirmWords }}</div>
    <div
      ref="moveDiv"
      @mousedown="mousedownFn($event)"
      :class="{ handler_ok_bg: confirmSuccess }"
      class="handler handler_bg"
      style="border: 0.5px solid #fff;height: 34px;position: absolute;top: 0px;left: 0px;"
    ></div>
  </div>
</template>

<script>
export default {
  name: 'JSlider',
  data() {
    return {
      beginClientX: 0 /*距离屏幕左端距离*/,
      mouseMoveStata: false /*触发拖动状态  判断*/,
      maxwidth: '' /*拖动最大宽度，依据滑块宽度算出来的*/,
      confirmWords: '拖动滑块验证' /*滑块文字*/,
      confirmSuccess: false /*验证成功判断*/
    }
  },
  methods: {
    isSuccess() {
      return this.confirmSuccess
    },
    mousedownFn: function(e) {
      if (!this.confirmSuccess) {
        e.preventDefault && e.preventDefault() //阻止文字选中等 浏览器默认事件
        this.mouseMoveStata = true
        this.beginClientX = e.clientX
      }
    }, //mousedoen 事件
    successFunction() {
      this.confirmSuccess = true
      this.confirmWords = '验证通过'
      if (window.addEventListener) {
        document.getElementsByTagName('html')[0].removeEventListener('mousemove', this.mouseMoveFn)
        document.getElementsByTagName('html')[0].removeEventListener('mouseup', this.moseUpFn)
      } else {
        document.getElementsByTagName('html')[0].removeEventListener('mouseup', () => {})
      }
      document.getElementsByClassName('drag_text')[0].style.color = '#fff'
      document.getElementsByClassName('handler')[0].style.left = this.maxwidth + 'px'
      document.getElementsByClassName('drag_bg')[0].style.width = this.maxwidth + 'px'

      this.$emit('onSuccess', true)
    }, //验证成功函数
    mouseMoveFn(e) {
      if (this.mouseMoveStata) {
        let width = e.clientX - this.beginClientX
        if (width > 0 && width <= this.maxwidth) {
          document.getElementsByClassName('handler')[0].style.left = width + 'px'
          document.getElementsByClassName('drag_bg')[0].style.width = width + 'px'
        } else if (width > this.maxwidth) {
          this.successFunction()
        }
      }
    }, //mousemove事件
    moseUpFn(e) {
      this.mouseMoveStata = false
      var width = e.clientX - this.beginClientX
      if (width < this.maxwidth) {
        // ---- update-begin- author:sunjianlei --- date:20191009 --- for: 修复获取不到 handler 的时候报错 ----
        let handler = document.getElementsByClassName('handler')[0]
        if (handler) {
          handler.style.left = 0 + 'px'
          document.getElementsByClassName('drag_bg')[0].style.width = 0 + 'px'
        }
        // ---- update-end- author:sunjianlei --- date:20191009 --- for: 修复获取不到 handler 的时候报错 ----
      }
    } //mouseup事件
  },
  mounted() {
    this.maxwidth = this.$refs.dragDiv.clientWidth - this.$refs.moveDiv.clientWidth
    document.getElementsByTagName('html')[0].addEventListener('mousemove', this.mouseMoveFn)
    document.getElementsByTagName('html')[0].addEventListener('mouseup', this.moseUpFn)
  }
}
</script>

<style scoped>
.drag {
  position: relative;
  background-color: #e8e8e8;
  width: 100%;
  height: 34px;
  line-height: 34px;
  text-align: center;
}
.handler {
  width: 40px;
  height: 32px;
  border: 1px solid #ccc;
  cursor: move;
}
.handler_bg {
  background: #fff
    url('')
    no-repeat center;
}
.handler_ok_bg {
  background: #fff
    url('')
    no-repeat center;
}
.drag_bg {
  background-color: #7ac23c;
  height: 34px;
  width: 0px;
}
.drag_text {
  position: absolute;
  top: 0px;
  width: 100%;
  text-align: center;
  -moz-user-select: none;
  -webkit-user-select: none;
  user-select: none;
  -o-user-select: none;
  -ms-user-select: none;
}
</style>
